Protective device for bus-bar circuits.



P. TORCH|O & H. R. WOODROW. PROTECTIVE DEVICE FOR BUS BAR CIRCUITS. APPLICATION FILED OCT. 28. 1914.

Patented Aug. 10, 1915.

annual wow %1 Manna-m v UNI ED sraa'rn s iaa PHILIP 'ronomoann HARR 'R. woonn ow, or,1\i-nw YonK,.n.- Y., AssmnoRs-To THOMAS E. MURRAY, or NEW YORK, 1\ T,-Y.

nrrr ore-10E.

rnorncrivn nnvicn non nus-ianncinounrs.

' Application filed October 28,

To all whom'itmay concern Be it known thatwe, PHJLII Tonorrro and HARRY RKVVOODROW, citizens of the United States, residing at New -York, in the county of New York and State ofNeiy York, have invented a certain new and useful Improve" ment in Protective Devices for Bus-Bar Circuits-of which the following is a specification. I The invention is a protective device for busbar circuits. I a

In our Patent No. 1,133,338, March 30, 1915," we have describedabusbar circuit 's'ec't-ionali'zed" by asystem of reactan'ce coils,

in series circuit, and a correlated system of alternating current generators or group of generators, one for each'reactance coil, the terminal leads of said generators or group of" generators being connected to taps on their. respective reactance coils. By this system of connections we obtained the result of maintaining-at full generation of voltage,

in case of a short 'circuit on thesystem, all

the busbar sections except the section affected by theshort circuit.

Our: present invention 18 an improvement of the aforesaid lnvention and provides in combination with. an unsectionalized main connected to a tap on said reactance coil.

busbar, a system of multiple connections consisting of reactance coils each having one terminal connected to the main busbar and the other terminal connected to an independent distributing bus and each reactance coil having a generator, or group of generators,

- Theaccompanying drawing is an electrical diagram symbolically illustrating our invention.

A is the main busbar circuit to which are connected in multiple reactance coils B, C, D. Alternating current alternators E, R0? are connected to said reactance coils at taps between the coil terminals. 7

I, J, K are independent distributing buses,

L, M, N are branch leads or feeders connected to distributing buses I, J, K. Under normal conditions each of the generators E, F, G is regulated to generate an equal share of the total output of the feeders L, M, N.

' If, forinstance, each of the feeders L, M, N.

generators except the synchronizing current required to maintain the parallel-operation of the generators. If, however, some ofthe Specification q Patent. Patented A11 10, 1915.

distributingbuse's L,'I\I, N- require more 'c'urrent than others, then thc generators on the less loaded sections of distributing buses will furnish the -surplus current, generated in excess of the requirements of their correlated. distributing buses to the more heavily loaded section of distributing buses; This transfer of current will take'place through the main bus A, and the reactancecoils B, .G, D. -In such case the current of a genance coil-B, one portion going to the distributing bus I and the other portion to the bus A, and hence to the more heavily loaded section of, say, bus J, byway of the reerator like E may divide itself in its reactactance coil C. To force this last-named portion .of current through the reactances intervening between" the terminal of generator E and J, the voltage of generator E must increase by the corresponding amountof voltage lost in these reacta-nces. This voltage would be too high for maintaining the proper voltage regulation on bus I were it not .for the influence of the mutual inductance of the two portions of the reactance'coil B carrying currents in opposite directions. The current which flows from the terminal of generator E to bus A will induce in the section of reactance B,- between generator t'erminal and I, a counter- GlQQtI'OIHOtlVQ. force proportional to the amount which the voltage of generator E has been increased. In this-manner the voltage of the distributing buses J, K are. kept all at practically the same potential regardless of the amount any one carries.

Consider the case in which one of the distributing buses I, J, K, or correlated feed.- ers L, M, N may be short-circuited. Letus assume that the short-circuit is at Xon bus I. Generator E becomes short-circuited through the portion of reactance coil B betweenits terminal and. I, and generators F of current which and G through the reactances between their respective terminals and main bus .A in

series with reactance B. The greater impedance to. the flow of current offered by the latter reactances tends to throw more of the short-circuit current on generator E. This current flowing through the portion of reactance coil 13 between the terminal of generator E and I induces by mutual induction in the reactance between the terminal of generator E and main bus A a counter elecr tro-motive force proportional to the drop in the former portion, thereby maintaining the voltage on bus A and the rest of the undamaged system at practically its normal value, Without being affected by the short circuit X on bus I.

IVe claim: In combination with a main bus, at plurality of reactance coils connected at one 15 end to the main bus, a plurality of independent distributing buses one each connected to the remaining terminals of the reaetance coils, and a generator or group of generators, connected to a tap on each of 20 said reactance coils. 

